Conventionally, there is a known heating device mounted in a vehicle such as an automobile (i.e., an in-vehicle heating device), which is installed on a lower part of a vehicle seat and which warms up the feet of a user.
For example, Patent Literature 1 discloses a vehicle-use seat capable of cooling and heating, for example, the feet of a user seated on the seat by utilizing small energy. The vehicle-use seat includes: an air feeder provided on a seat cushion or a seat back; an air intake duct and an air discharge duct extending from the air feeder; and a heat supply unit. The air intake duct includes an intake opening, which is open at the front of the seat cushion. The air discharge duct includes a discharge opening, which is open at the front of the seat cushion. The heat supply unit supplies hot energy or cold energy to air that flows from the intake opening to the discharge opening.